Internet Protocol TeleVision (IPTV) is a system through which television-type content and services are delivered using the Internet Protocol (IP) over packet-switched networks, such as the Internet and most modern wireless telecommunication networks. IPTV is distinguished from various applications that transfer video files across networks, by an ongoing standardization process and deployment in subscriber-based telecommunication networks featuring tightly managed network security and performance, allowing a high Quality of Service (QoS) and enhanced user experience. IPTV subscriptions typically require at least one cooperative network node, referred to herein as a Set-Top Box (STB), installed at the subscriber premises. IPTV services may be classified into three main types: live (i.e., real-time) broadcast television, time-shifted television (e.g., replays of previously broadcast television content), and Video on Demand (VoD). VoD offerings typically comprise movies, as opposed to television content.
VoD is generally offered as a streaming service, such as Real Time Streaming Protocol (RTSP), or as a download service, such as HTTP download. VoD streaming service is used in IPTV deployments where the available bandwidth over the last mile (i.e., in the access network) is greater than the bandwidth required by the stream. VoD download service has no specific bandwidth requirements; the media content downloads in the background and when completed, the user is notified that he or she may begin to play it.
Rental movies are the content typically offered through the VoD service, including VoD download service. In this case, the movie asset within the offering package references the entire VoD media file. A Download Manager application within the STB must either download the media file fully before starting to play it, or utilize a Progressive Download delivery method, whereby the play can start before the file is been fully downloaded.
Another type of content offered through the VoD service, including VoD download service, is called logical content. A logical content offering is one or more clips, or portions, of a movie or other VoD media file. As a practical implementation matter, it is not feasible to download an entire VoD media file to the STB and play only a portion of it, considering the impact on the bandwidth consumed and the download time. The bandwidth available for the VoD download service is generally limited; hence, such an implementation is not user friendly or cost effective.
There are three known solutions addressing the logical content download optimization problem: Content/Asset Management System (CMS/AMS); server-based logical content clipping; and client-based logical content clipping.
The CMS/AMS solution generates, at logical package creation time, a new VoD package for download, which contains the clipped media file. In this solution, each time a new logical content is defined, the base movie asset (i.e., a VoD media file) must be decrypted and clipped, and the logical content re-encrypted. The decryption/re-encryption process is resource intensive, and is therefore disfavored by operators.
In server-based logical content clipping, a logical content package, which contains start and end time markers for the base asset, is created. For example, the start/end time markers may comprise startNPT/endNPT (Normal Playback Time) markers, that measure elapsed time from a specific temporal point within the VoD media file (e.g., NPT=0 or the Beginning Of Stream, or BOS, marker). At package ingestion, the Download Media Server downloads the entire media file from a CMS/AMS. The STB retrieves the startNPT/endNPT markers from an IPTV Application Server (AS) at the time of purchasing the logical content offering. The STB then requests a time-range download from the download media server. However, most media servers support byte-range partial file download, as this is standard in the HTTP protocol (range header), but do not in fact support time-range downloads. The time-range download is not supported in standards published by standards bodies such as the Internet Engineering Task Force (IETF). Therefore, media server manufacturers do not have any incentive to implement this method.
In client-based logical content clipping, the STB obtains the temporal start/end markers from the IPTV AS upon purchasing the VoD offering. The STB then downloads the entire VoD media file from the download media server, but only plays (as specified in the purchased VoD offering) the time range delimited by the temporal markers. The obvious drawback of this solution is that the entire VoD media file must to be downloaded to the STB, but only a small portion is rendered to a user. This wastes bandwidth in any scenario, but in the particular case of low bandwidth in the last mile access network, would result in long download time. This is especially critical when the logical content is only a small segment of a long movie, as in the case of movie advertisement.
There exists a need in the art for an efficient system and method of delivering VoD logical content to a plurality of STBs, without wasting bandwidth and by utilizing industry-standard file fragmentation protocols.